Herbicides are very useful for controlling certain weeds in the presence of growing crops. However, many herbicides injure certain crop plants slowing growth and development at rates necessary to kill or stunt weeds. Accordingly, some herbicides cannot be used for controlling weeds in the presence of certain crops. Obviously, a safening agent which consists of a chemical compound that is to be used to treat either the seed of the crop plant, the crop plant locus, or the crop plant itself, to reduce the injury due to application of a herbicide without a corresponding reduction of herbicidal action on weeds, is quite beneficial. The compounds of the present invention can be used to prepare certain 2-substituted-4-substituted 5-thiazolecarboxylic acids and derivatives thereof, which are effective herbicidal safeners as disclosed in co-pending Ser. No. 905,682 and Ser. No. 906,183, and Application Ser. No. 080,751, filed Oct. 1, 1979 titled "2-Chloro-4,5-Disubstituted Thiazoles Useful As Herbcidal Safeners" by Robert K. Howe and Len F. Lee, the disclosures of which are herein incorporated by reference.